U.S. Pat. No. 9,828,974 to Oney, incorporated herein by reference, discloses a seawater extraction system to use deep ocean seawater for cooling for offshore process applications including a submersible pump, a pipe and riser, a floating vessel, a transfer pipe, and a cooling water heat exchanger system.
U.S. Pat. No. 7,658,843 to Krock, et al, incorporated herein by reference, discloses a system to extract sea water from a depth in excess of 400 meters below the sea surface, and then to desalinate and store desalinated sea water to produce potable water.
However, although the prior art discloses the general concept of a vertical flexible pipe (a “riser”) for pumping deep ocean seawater into a floating vessel, there are very substantial technical problems that must be overcome by any apparatus, system or method to harvest seawater from substantial depths, at the very least because of the uncontrollable and unavoidable motion of a floating vessel in the ocean or seas, especially directly after a natural disaster.
Further, the very substantial depths from which deep ocean seawater must be raised to reach the surface, raise technical problems that have not been disclosed or overcome by the prior art.
It is self-evident that a vessel to harvest deep seawater must have a sufficiently long riser to reach the desired harvesting depth, but the riser must be sufficiently compact for transportation on the vessel, yet rapidly deployable when the vessel reaches a desired location. A sufficiently long single piece rigid riser would be so long it would be difficult to fit on a vessel for transportation, especially in rough seas. Multiple segments of a riser that could be joined together to form a sufficiently long riser would take up too much space and/or take too long and be too difficult to assemble. Further, because the vessel will naturally move, the riser must be flexible, and cannot be rigid, or else it will break when the vessel moves. Thus, a riser that is flat when not in use and can be rolled onto a spool would be desirable, such as a fireman's hose. However, a riser that is flexible enough to be flattened, and then rolled (and unrolled) onto a spool, will also stretch under its own weight.
Further, a submersible pump at the submerged end of the riser must be provided with sufficient electrical power in order to be able to pump a sufficient amount of water to the surface. Batteries, solar cells, or other devices at the submerged end cannot provide sufficient power. Thus, the submersible pump, which is to be submerged at a great depth, must be powered remotely, usually by power from a vessel, transmitted by a power cable. But the amounts of power necessary to pump sufficient amounts of seawater up from the depths require that the power cable be quite substantial in weight and diameter, so that sufficient current can be efficiently carried by the cable along its full length and provided to the submersible pump (just as a pipe carrying water must have a large diameter to efficiently carry a large amount of water, an electrical cable carrying electricity must have a large diameter to efficiently carry a large electrical current). The weight of such a length of cable will therefore cause the cable to stretch from its own weight. But because the cable usually contains metal or other wiring, the amount the cable will stretch will probably differ from the amount the riser would stretch. Thus, the vertical riser and the power cable cannot be joined together along their length as a single structure. If the vertical riser stretches more than the power cable, then the cable will bear the weight of the riser and submersible pump, and either break or separate from the submersible pump, causing a breakdown. If the power cable stretches more than the vertical riser, then the riser will bear the weight of the cable (which is quite substantial because the cable must carry sufficient current, as described above), and break, or the power cable's own weight will cause the cable to separate from the submersible pump, again causing a breakdown.
Also, when the submersible pump with a separate riser and power cable are raised to the surface, the riser and power cable will tangle with each other (fouling).
For a further example, a vessel will pitch, roll and yaw when on the ocean, which may cause the vessel to come in contact with the riser or the power cable, chafing against a flexible riser or the power cable, and breaking a rigid riser or the power cable. Such collisions could be especially damaging to the riser or the power cable if either comes in contact with the chine of a vessel: the chine is a sharp change in angle in the cross section of a vessel hull. If a riser or the power cable collides with this sharp change in angle, the riser or the power cable could be severely damaged.
Moreover, it may be prohibitively expensive to build specialized vessels to incorporate devices for harvesting and desalinating seawater. Many cargo vessels are now built to receive and transport intermodal shipping containers of various sizes, which often (but not always) conform to standards set by the International Standards Organization (“ISO”), so they are often referred to as ISO containers. Such shipping containers have fittings (corner castings) on their corners that can accept “twistlocks” to allow containers to be easily attached to, and detached from, each other, or to vessels or other modes of transportation (such as railroad cars or trucks). A majority of mass produced goods are now shipped using shipping containers on cargo vessels configured to receive intermodal shipping containers.